Pipe calipering tools



March 4, 1958 Find may 27. 1954 M. M. KINLEY ET --AL PIPE cALxPEmNG Toons 4` sheets-sheet 1 Afro/wf y@ Filed May 27. 1954 March 4, 1958 M. M. KINLEY ErAL r 2,825,141

PIPE CAMPER-ING TooLs 4 Sheets-sheet 4 AHORA/Vg PIPE CALIPERING TODLS Myron M. Kinley and Frank F. Robertson, Houston, Tex.;

said Robertson assignor to M M. Kinley Co.,l Houston, Tex.

Application May 27, 1954, Serial No. 432,764

Claims. (Cl. 33-17S) v T his invention relates to nev/.and useful improvements in pipe calipering tools.

An object of this invention is to provide a new and improved pipe calipering tool for use in a pipe, wherein a maximum number of contact members for contacting the inside surface of the pipe is provided, so that substantially the entire inner surface of the pipe being calipered is contacted, whereby a more complete indication of the condition of the inside surface of the pipe is obtained.

An important object of this invention is to provide a new and improved pipe caliper tool for obtaining a record of the surface irregularities on the inside of a pipe, wherein the contact members for contacting the inside of the pipe are relatively thin and are pivotally mounted on the tool for dragging contact with the inside surface of the pipe as the tool is moved through the pipe for making the record of the surface irregularities in the pipe, with each of said members being guided throughout substantially its entire length to prevent twisting thereof despite the relative thinness of the members.

Another object of this invention is to provide a new and improved caliper tool for use in well pipe or other types of pipe, wherein the means for contacting the inside surface of the pipe being calipered includes a plurality of individual feeler members which are separably mounted on the housing of the tool and are suspended in said housing at the pivot portion of each of the feeler members, the housing of the tool being formed with guide slots` for guiding the pivotal movement of the feeler members toward and away from they inside surface of the well pipe.

Still another object of this invention is to provide anew and improved pipe calipering tool, wherein the contact means for contacting the inside of the pipe being calipered includes a plurality of feeler members which are pivotally mounted in the tool for radial movement in accordance with the surface irregularities in the pipe', such feeler members being urged radially outwardly into engagement with the inside surface of pipe by a plurality of resilient members in the tool, said tool having guide slots therein for guiding the lateral or radial movement of the feeler members and the resilient members.

A further object of this invention is to provide a new and improved pipe caliper tool wherein the feeler members for contacting the inside surface of the pipe being calipered are so constructed and so mounted that each of the feeler members can be constructed from separate pieces which are adapted to be formed separately by stamping same from metal or the like.

A still further object of this invention is to provide l;

in a pipe caliper tool a new and improved means for locking the feelers or pipe engaging members in aretracted position as the tool is moved through the pipe in one direction, whereby said feelers or pipe engaging members are held out of contact with the pipe until it is desired to obtain a record or indication of the condition of the inner `Surface of the pipe.

ICC

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specication and by reference to the accompanying drawingsbforming a part thereof, wherein an example of the invention is shown, and wherein: l

Figures 1A and 1B are vertical sectional views, which together illustrate the improved portions of the pipe caliper tool of this invention, with the portion shown in Figure lA being positioned above the portion shown in Figure 1B. I

Figures 2A and 2B are views, partly in elevation and partly in section, which together illustrate the improved portions of the caliper tool of this invention as viewed from the left sides of Figures 1A and 1B, respectively.

Figure 3 is a horizontal sectional view, taken on line 3-3of Figure l.

Figure 4 is a vertical sectional View illustrating the construction of the body of the tool of this invention.

Figure 5 is an elevation, illustrating the resilient means or urging means of the tool of this invention.

Figure 6 is a horizontal sectional view, illustrating a portion of the construction illustrated by Figure 3,

Figure 9 is a horizontal sectional view taken on line -9 of Figure 7.

Figure l is an isometric view illustrating one of the resilient or spring members shown in Figure 7.

In the drawings, the numeral 10 designates the body or Y housing of the caliper tool of this invention, which is adapted to be lowered into a well pipe or casing C for obtaining an indication or a record of the surface irregularities on the inside of the pipe or casing C. Thek body or housing 1i) has contact members or feeler members 11 pivotally mounted thereon with springs or resilient members 14 being mounted on the housing 10 for urging the feeler members 11 outwardly into engage- .ment with the inside surface of the well pipe or casing C.

The feeler members 11 are so mounted on the housing 10 that they are adapted to pivot inwardly and outwardly in response to the surface irregularities in the inner surface of the pipe or casing C with the upper ends of the feeler members 11 being adapted to Contact a cone or transmitting member 15, so that the pivotal movement of the feeler members 11 is transmitted into longitudinal movement o-f the cone or transmitting member 15. Such movements of the cone 15 are indicated or recorded in the usual manner for calipering tools and as illustrated in the drawings, a rod 16 extends upwardly from the cone 15 and nas connected thereto a rod 17, a pivoted bell crank arm 18 and a stylus or recorder member 1.9, which stylus 19 traces or marks a line L on a tape or recording chart 20. The line L is a record, therefore, of the movement of the feeler members 11 in response to the surface irregularities on the inside of the pipe or casing C. The cart 20 may be driven by any known means such as a spring or by a contact roller engaging the inside surface of the pipe or casing C, as shown in the United States Patent No. 2,544,609 issued to D. B. McMahan. As is usual with such constructions, if the stylus 19 is not moved laterally by the action of the cone 15, the relative movement between the stylus 19 and the tape or chart 20 by reason of the longitudinal movement of the .Fatented Mar. 4, 1958 j tape or chart would cause the line L to be simply `a straight, smooth line. However, when longitudinal movement is imparted to the cone 15 from the feeler members 11, and thus lateral movement is imparted to the stylus 19, the stylus 19 is caused to move laterally in response to the movements of the feeler members 11, and, as will be explained, the feeler member 11 which is moved furthest outwardly controls the movement of the member 19. Thus the stylus member 19 actually traces. a line L, which has lateral variations therein.

Each of the feeler members 11 is preferably formed by stamping same from metal or similar material; the sides are substantially flat and parallel, and the thickness of each feeler member 11 is substantially uniform throughout its length (Figure 6), except that the contact portion 11a`of each `feeler member is preferably slightly tapered (Figure 8). The contact portion 11a o-f each feeler 11' is preferably formed of a hard surfaced material such as tungsten carbidek to reduce` the wear on the surface contacting the inside of the pipe or casing C. WithV the tool being constructed for making a record or indication' ot" surface irregularities in the pipe or casing C upon an upward travel of the tool A therein, as shown in the drawings, thecontact portions 11a of the feelers 11 are at substantially the lowermostpoint of each feeler 11. of the feelers 11 has a pivot portion 11b, which includes an outer curved recess 11c and an inner curved surface 11d. The inner curved surface 11d of each feeler 11 contacts a generally cylindrical back-up element 22, which is pressed into the bore'of the body or housing 10 on the inside thereof or is otherwise firmly held therein. Each of the curved inner surfaces 11d contacts the concave circumferential outer surface 22a in the back-up element` 22. A pivot ring 25, which is generally formed in two parts (Figure 3), surrounds all the feelers 11 and fits within the outer recesses 11e of the feelers 11, whereby the feelers are adapted to pivot about the ring 25, as will be explained. The ring 25 is held in position within the recesses 11c by a removable sleeve 26 (Figures 1B, 2B, 3 and 6), so that the feelers 11 are actually retained in position by the sleeve 26, but can be removed from the body or housing 10 when the sleeve 26 `and the ring 25 are removed.

The upper ends 11e of each ofthe feelers 11 contact the inclined or tapered surface 15a of the cone 15, so that the pivoted movements of the feelers 11 are transmitted to the cone -15`. llhe rod 116, which is connected to the cone- 15, is `guided in its' longitudinal movement by a gnidefbushihg 30, which is mounted at-tne upper end of th'etbod'y 10 and is secured ,theretoy by'screws 31 or similar securing means. The upper endv ofthe body is Each formed with external threads 10a, to which is connected 'a cylindrical body 32, which forms a continuation of the body 10 and which surrounds the recording structure. A

frame, formed by two parallel plates 33 and 34 secured i to the bushing 30 by screws 35, extends upwardly from the bushing 30 into the cylinder body 32. The rod 16 is provided with a lateral extension 16a, which extends through a longitudinal slot 33a in the frame plate 33 and which has a threaded connection to the threaded end 17a of the rod 17, whereby the rod 17 moves longitudinally in accordance with longitudinal movement 'of the rod 16.

For holding the rod 16 against longitudinal movement and for thereby `holding the feelers 11 in a retracted or inactive position (Figure lB) a locking device R (Figure lA) is provided, and it includes a laterally extending shaft 36 mounted between the plates 33 and 34 for piv otal movement relative thereto. A clevis 37 is welded. o'r otherwise secured to the pivoted shaft36,.and it carries. a pin 37a on which is mounted a cylindrical roller 38, which engages the upper end of the rod 16 when the lock ingldevice R is in the latching or locking position (Fig ure' 1A) to maintain the cone 15 in a lower position, whereby the feelers 11"are maintained retracted or piy'rf 4' t oted inwardly (Figure 1B). It will be evident that when the feelers 11 are so held, they cannot move outwardly; and they do not contact the inside surface of the well pipe C.

A coil spring 39 or a similar resilient means urges the shaft 36 to pivot or turn so as to swing the clevis 37 and roller 38 upwardly to a released position (shown in dotted lines in Figure 2A) but during the lowering of the caliper tool in the well, such Vspring release action is prevented from releasing the roller 38 from its seated position on the upper end of the rod 16 by the engagement of a lug 4G on the clevis 37 with a latching arm 41, which extends laterally through a longitudinal opening 34a in the plate 34 and has connection with an actuating release rod 42 extending upwardly between lthe plate 34 and the cylinder 32. To release the latching arm 41 from engage ment with the lug 40, the release rod 42 is moved downwardly by any suitable device such as that shown in the aforementioned McMahan patent, whereby ther arm 41 is moved downwardly below the lug 40 so that the urging of the spring 39 takes effect to swing the roller 38 upwardly and away from the upper end of the rod 16.

When the locking device R is released, which preferably is caused to occur after the calipering tool has started its upward movement in the well pipe, then the rod 16 is forced to move longitudinally in accordance with the pivotal movement of the feelers 11. It will also `be evident that the spring members 14 then can urge the feelers 11 outwardly into engagement with the well casing or pipe. C. The feeler or feelers 11 whichmove the furthest outward will transmit such movement to the cone 15. To maintain the cone 15 seated on the upper end 11e of the feeler 11 which has moved the furthest outwardly, a spring 44 is connected to the bell-crank arm 18 and a support strip 45 fixed to the plates 33 and 34 (Figures lA and 2A). Since the rod 17 is also connected to the bell crank arm 18 below a pivot pin 46 thereof, the `spring 44 tends to pivot the arm 18 to the left or counterclock wise about the pivot pin 46(Figure 1A) and thereby urges the rod 17, rod 16and cone 15 downwardly. It will be understood, of course, that the spring 44 is of a lesser strength than the springs 14, so that the spring 44 does not have sufficient force to retract the feelers 11 `from engagement with the inner surface of the well pipe C.

As shown in Figures 1A and 2A, the chart 20 is in the form of a tape, which is unwound from roll 50 upwardly pa'st the' stylus '19. The roll 50 is held in position by a leaf spring 51 mounted between the platesr33 and 34. The unrolling' or longitudinal movement'of the tape 20 can be accomplished by any suitable construction, one of which is shown in the aforementoned McMahan patent. It should also be pointed out that the calipering tool can be raised and lowered on any suitable support, but preferably the cylinder 32 or an upper extension thereof is suspended from a wire line or cable (not shown) extending `to the surface of the well. Of course, it will be understood that the particular recording structure and locking structure illustrated in Figures 1A and 1B are not the only types of such structures which can be used with the calipering tool of this invention, since many types of recording or indicating devices and locking devices are known for use with pipe calipering tools, including devices 4for indicating or recording at'the surface of the ground.

The springs or resilient members 14, which serve to urge the feelers or feeler members 11 outwardly toward contact with the inside surface of the pipe or casing C, may be formed, as shown in Figures 1B and 5, in a cluster arrangement whereby the lower ends are formed as a unit 14a, which is annular in construction, so that the springs 14 can be assembled as a unit in the body or housing 10. There are the lsame number of springs orresilient member's 14 as there Vare feelers or feelermembers 11,1and the upper end 14b of each spring 14 contacts one of the feelers 11 at its inner surface near the lower end thereof to urge each feeler 11 outwardly toward contact with the pipe C:

In Figures 7, 9 and 10, a modified construction of the springs or resilient members 14 of Figures 1B and 5 is shown, wherein the springs 114 are each separately formed instead of being formed in a cluster. The lower end 114a of each spring 114 extends inwardly to provide a shoulder 114b, so that they can be held in the housing 10 by an annular shoulder 56a on a retaining plug 56, which is fixed in the housing 10 by a screw 57. The upper end 114C is formed like the upper end 14b of each spring 14. It can be observed that each spring 114 is of uniform width throughout its length, but is of increased thickness at its lower end, whereas each spring 14 is of uniform thickness throughout its length, but is of increased width at its lower end. Both forms of the springs 14 and 114 are therefore adequately strengthened at their lower ends, but the springs 114 can be manufactured by stamping from metal sheets, whereas, since the springs 14 are formed with the cluster ring 14a, they are generally formed by a milling or lathe operation.

In order to guide the lateral or radial movement of the feelers 11 and the springs 14 as they move in response to the surface irregularities encountered in the inside of the casing or pipe C, the body 1) is formed with a longitudinal slot 10b for each feeler 11 and its corresponding spring 14 (Figures 4 and 6). Thus, the guide slots 10b direct the pivotal movement of the feeler members 11 about the pivot ring 25 in a radial or lateral direction.

The body 10 is also formed with threads 10e at its lower end for receiving a threaded nose plug 55 (Figure 1B) upon which the annular ring 14a at the lower ends of the springs 14 rests. An annular recess 10d is also formed in the body 10 to correspond with the position at which the recesses 11e` of the feelers 11 are positioned, so that the ring 25 actually seats in the recesses 11e and in the annular recess 10a' to further assist the ringv 25 in retaining the fingers 11 in their suspended position in the body 10 by preventing vertical motion of the feelers 11.

It should be particularly pointed out that one of the main advantages of the particular construction of this invention is that a large number of feelers or feeler members 11 may be utilized, whereby substantially the entire inner surface of the casing at a particular elevation can be contacted simultaneously. However, for clarity, the drawings have been illustrated with only a few feelers 11, except for Figure 6, which is shown in detail to illustrate the large number of feelers 11 which can be employed with the tool of this invention. In fact, it has been found that with the particular construction of this invention, the feelers 11 can be spaced as close as twelve degrees apart and effectively used, while retaining suiiicient strength in the body 10 and the feelers 11 for obtaining eiiicient operation of the tool.

in the operation or use of the caliper tool of this invention, it is lowered into the pipe or casing C which is to be calipered. The record or indication of the surface irregularities on the inside of the pipe or casing C is made as the tool A is raised in the pipe or casing C. During the lowering operation, the feelers 11 may be held in' the retracted position by the locking means R (Figure lA). When the lowermost point in the pipe or casing to be calipered has been reached, then the tool is raised upwardly by raising the cable or wire line upon which the tool is suspended. As the tool is raised, the springs 14 or the springs 114 (whichever modiiication is used) constantly urge the feeler members 11 radially outwardly into contact with the inside surface of the pipe or casing C. Since the feeler 11, which moves the furthest outwardly at any given point during the raising of the tool will have its upper end 11e furthest inwardly, the feeler that is furthest outward will be the one which urges the cone 15 upwardly and the single line L which is recorded on the chart 2t) will at all times be a record of the feeler which has moved the furthest outwardly at each instant of travel of the tool upwardly in the pipe. 0f course, there may be more than one feeler at the same distance outwardly, and, therefore, more than one feeler may actually be the furthest outwardly, but the other feelers will be out of contact with the cone 15.

Thus, with a feeler 11 extending into a pit or hole P (Figure 7), that feeler 11 will be the furthest outward and will be the one which moves the cone 15 and the stylus 17 the furthest distance upwardly. Since it is desired to obtain a record of the deepest pit or of a hole in the pipe or casing at each elevation as the tool is raised in the pipe, it is particularly important to have as large a number of the feelers 11 as possible, and this invention provides for a maximum number of feelers within the limits of the strength and rigidity requirements.

As the various feelers 11 move in and out of the pits or holes in the casing C, the feelers will, of course, pivot about the pivot ring 25 with the rear surface 11d of each feeler 11 sliding against the back-up element 22. 1t should be pointed out that with the particular construction of the caliper tool of this invention, the contact portions 11a of the feelers 11 follow the pivot portions 11b of the feelers 11 as the tool is raised in the pipe C, so that the feelers 11 actually have a dragging contact with the inside surface of the pipe or casing C. ri`his prevents a combination compression movement being applied to the feelers 11, which, in prior devices, has been known to cause the feelers 11 to jump or move inwardly to give a false or spurious indication or record and possibly to miss a pit or opening in the well pipe or casing C. Furthermore, it reduces the danger of breaking the relatively thin feeler members 11, which thiuness is particularly desirable in order to have a maximum number of feelers in the tool. Since each ot' the feeler members 11 is guided throughout substantially its entire length by the longitudinal radially extending slots 19h in the body 1) during their pivotal movement, the feelers 11 can be made or a thinner material while maintaining sufficient resistance against bending or twisting of the feelers 11 and at the same time assuring the radial movement in the same plane for each pivotal movement of the respective feelers 11. It will also be noted that the springs 1d and 114 are also guided by the slots 1Gb so that they are likewise prevented from being twisted or bent.

Also, should it be necessary to replace or repair one of the feelers 11, it can be readily removed by Unthreading the body extension 32 and sliding the retaining sleeve 26 upwardly and away from the body )iti to expose the pivot ring 25. With the pivot ring 2S formed in two sections, as is preferable, it may be readily removed and then the feelers 11 can be slipped outwardly thro-ugh the slots 1% to replace them individually if desired.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may he made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

l. ln a pipe calipering tool having a chart member, a stylus adapted to contact said chart member, drive means fordriving said chart member relative to said stylus, and activating means for varying the relative vmovement between said chart member and said stylus va contact portion adapted lfor engaging said pipe and a pivot portion at its outer edge for pivotal movement thereof, said contact portion being positioned to follow said pivot portion as said feelers are moved in the said one direction along said pipe, and means for guiding each of saidfeelers throughout substantially its entire and bending lengthv to prevent twisting thereof despite the relative-` thinness of said feelers.

2. ln a. pipe calipering tool adapted to record surface variations in a pipe and having` a recording chart, a recorder meansfor making a record` on said chart` drive means for driving said chart relative to said recorder means, and activating means for varying the relative movement between said chart and said recorder means in response `to surface variations of said pipe, the improvement residing `in the activating means. includingl a convex `cone mounted in said tool, a ilat fccier member pivotally mounted in said tool for dragging contact with said pipe, resilient means for urging said member laterally into Contact with said pipe, said member having a surface for contact with said cone for effecting a reciprocal mo-vement of said cone in response to the lateral movement of said feeler member.

3. In a pipe calipering tool adapted to record surface variations in a pipe and having a recording chart, a recorder means for making a record on said chart, drive means for driving said` chart relative to said recorder means, and activating means for varying the relative movement between said chart and `said recorder means in response to surface variations of said pipe, the improvement residing in the activating means, including a fulcrum ring on said tool, a sleeve for retaining said ring on said tool, a plurality of individual pipe engaging members each separately mounted in said tool and each bearing on said fulcrum ring, back-up means in said tool for contact by said pipe engaging members upon pivotal movement of said members` about said fulcrum ring, and resilient means for urging said members laterally outwardly toward said pipe as each of said members pivots about said fulcrum ring in response to the surface variations of said pipe.

4. In a pipe calipering tool adapted to record surface variations in a pipe and having a housing with longitudiual slots therein, a recording chart in said housing, a recorder means in said housing for making a record on said chart, drive means in said housing for driving said chart relative to said recorder means, activating means `in said housing for varying the relative movement between said chart and said recorder member in response to surface variations of said pipe, and means to move said housing through said pipe, the improvement residing in said activating means, including a plurality of individual feelers, each of said :feelers being mounted in said body for pivotal movement relative to said body, each of said feelers having a contact portion extending through said longitudinal slots and projecting exteriorly from said body for contact with said pipe, the pivot point of each feeler being in advance of its contact portion as said housing is moved through said pipe, whereby said feelers have a dragging Contact with said pipe, anda plurality of leaf springs in said housing each contacting one of said feelers at a point following said pivot portion of said feelers to urge said feelers toward said pipe.

5. In a pipe caliper tool adapted to record surface variations in a pipe and having recording means, means for contacting the pipe and adapted to be moved in `accordance with the surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means, the improvement residing in the contacting means, including a substantially cylindrical` housing, a plurality of feelers pivotally mounted in lsaid housing for contacting said pipe each feeler having a pivot portion adjacent the inner substantially cylindrical surface of said housing, a pivot means in contact with said inner substantially cylindrical surface and with said pivot portions to permit said feelers to pivot thereon, a plurality of springs contacting each of said feelers below said pivot portion thereof to urge them outwardly' of said housing, and radially extending guidesurfaces formedv insaid housing to direct the pivotal motion of said feelersV in radial planes. t

6. In a well caliper tool adapted to` record surface variations in apipe and having a recording means, means for contacting the'pipe and adapted to be moved in accordance `with the surface variations'in the pipe,` transmitting means for transmitting the movement of the contacting means to the recording means, the improvement residing in the contacting means, including a housing, a plurality of feeler members in said housing, a plurality of springs in said housing for contacting and urging said feeler members toward said pipe, said housing having a plurality of longitudinal radial guide slots for guiding said springs and said feeler members in radial planes, and pivot means foreach of said feeler members to permit said members to pivot thereon during radial movement thereof, said pivot means including a ring positioned circumferentially around said feeler members and with in the walls of said housing. n

In a pipe caliper tool adapted to record surface variationsv in a pipe and having a recording means, means for contacting the pipe and adapted to` be moved in accordance with surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means, the improvement residing in the transmitting and contacting means, including a housing, a plurality of feeler members pivotally mounted in said housing,` a plurality of springs for urging said feeler members toward said pipe, said housing having a plurality of radial guide slots through which said feeler members and said springs extend so that the walls of said slots guide said feeler members and said springs in radial planes, and a reciprocating `cone in said housing for contacting said feeler members to transmit the movement of said feeler members to said recording means, whereby a record of the surface variations in the pipe is obtained.

8. In a pipe caliper tool for recording surface variations in a pipe and having a recording means, contact means for contacting the pipe and adapted toA be moved in accordance with surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means whereby a record is made of such surface variations, the improvement residing in the contact means, including a housing, a plurality of feeler members mounted in said housing for contacting said pipe, said housing having a plurality of longitudinal radial slots through which said feeler members extend so that the walls of said slots guide same radially in response to the surface variations in the pipe, pivot means on said housing for said feeler members to pivot thereon, a plurality of springs in said housing extendingthrough and guided by the walls of said slots for urging said feelers outwardly of said housing, and a reciprocating means in said housing adapted to move in response to the movement of said feeler members.

9. ln a pipe caliper tool for recording surface variations in a pipe and having a recording means, contact means for contacting `the pipe and adapted to be moved in accordance with surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means whereby a record is made of such surface variations, the improvement residing in the Contact means, including a plurality of feeler members dispo-sed in said tool for contacting said pipe, each of said feeler members having a pivot portion, a substantially annular pivot means in said tool contacting each of said feeler members at its pivot portion and extending circumferentially about said feeler members, and said tool having longitudinal guide slots through which said feeler members extend for contacting said pipe to guide said feeler members during their pivotal movement about said pivot means;

l0. In a well caliper tool for recording surface variations in a pipe and having a recording means, contact means for contacting the pipe and adapted to be moved in accordance with the surface variations in the pipe, transmitting means for transmitting the movement of the 9. contacting means to the recording means whereby a record is made of suc'n surface variations, the improvement residing in the contact means, including a plurality of feelers pivotally mounted in said tool for contacting said pipe, each of said feelers having a recess in its outer surface, and a ring surrounding said feelers and contacting them in said recess to form a pivot for each of said feelers whereby said feelers are adapted to pivot about said ring in response to the surface variations in said pipe.

11. In a well caliper tool forV recording surface variations in a pipe and having Va recording means, contact means for contacting the pipe and adapted to be moved in accordance with the surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means whereby a record is-made of such surface variations, the improvement residing in the contact means, including a plurality of feelers pivotally mounted in said tool for contacting said pipe, each of said feelers having a recess in its outer surface, a ring surrounding said feelers and contacting them in said recess to form a pivot for each of said feelers whereby said feelers are adapted to pivot about said ring in response to the surface variations in said pipe, and a back-up element disposed in said tool, the inner surface of each of said feelers contacting said backup element during pivotal movement thereof about said rmg.

12. In a well caliper tool adapted to record surface variations in a pipe and having a recording means, means for contacting the pipe and adapted to be moved in accordance with surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means whereby a record is made of such surface variations, the improvement residing in the contact means, including a plurality of feelers pivotally mounted in said tool for contacting said pipe, each feeler having a pivot portion in its outer surface, pivot means in said tool, a portion of said pivot means surrounding said feelers and contacting them at said pivot portion to permit each of said feelers to pivot in accordance with the surface variations in the pipe, and radially extending guide surfaces on said tool to direct the pivotal motion of said feelers in radial planes.

13. In a pipe caliper tool adapted to be positioned in a pipe and having a body, a recording means within said body, contact means carried by said body for contacting the pipe and for moving in response to the surface variations in the pipe, transmitting means for transmitting the movement of the contacting means to the recording means whereby a record of the surface variations in the pipe is obtained, the improvement residing in the contact means, including a plurality of feelers pivotally mounted on said body and each having a pivot portion in its outer edge, pivot means for said feelers in contact therewith at said pivot portions to form a pivot for each of said feelers, back-up means contacting the inner edges of said feelers during pivotal movement thereof about said pivot means, and radially extending guide surfaces on the body to direct the motion of said feelers in radial planes during the pivotal movement.

14. In a well pipe caliper tool for use in a well pipe having a housing, recording means within the housing, contact means for contacting the pipe carried by the housing and longitudinally reciprocable transmitting means for transmitting surface variations in the well pipe from the contact means to the recording means as said caliper tool is raised in said well pipe, the improvement residing in the contact means including a plurality of feelers each having an upper portion for engagement with the transmitting means, a substantially annular fulcrum means in said housing for said feelers, each of said feelers having a contact portion for contacting said well pipe located below said fulcrum means, and urging means for urging said feelers radially outwardly whereby as each 10 feeler moves radially inwardly it pivots about said fulcrum means against the urging of said urging means.

15. In a well caliper tool for use in a well pipe having recording means, contact means for contacting the pipe, and transmitting means for transmitting surface variations in the well pipe from the contact means to the recording means, the improvement residing in the contact means including a housing having a plurality of lonigtudinal slots therein, a plurality of feeler members pivotally mounted on the tool and each of which includes a pivot portion on the outer edge thereof, and a pivot ring retained by said housing and extending transversely to said longitudinal slots to contact said feeler members at said pivot portions to retain Ysaid feeler members and to permit said feeler members to pivot about said pivot portions.

16. In a well caliper tool-for use in a well pipe having recording means, contact means for contacting the pipe, and transmitting means for transmitting surface variations in the well pipe from the conta-ct means to the recording means, the improvement residing in the contact means including a housing having a plurality of longitudinal slots therein, a plurality of feeler members pivotally mounted on the tool and each of which includes a pvot portion on the outer portion thereon a pivot ring retained by said housing and extending transversely to said longitudinal slots to contact said feeler members at said pivot portions to retain said feeler members and to permit said feeler members to pivot about said pivot portions, and a back-up element mounted in said housing, the inner surface of each of said feelers contacting said back-up element during pivotal movement thereof about said pivo-t ring.

17. In a well caliper tool for use in a well pipe having recording means, contact means for contacting the pipe, and transmitting means for transmitting surface variations in the well pipe from the contact means to the recording means, the improvement residing in the contact means, including a plurality of at, thin feeler members each adapted for sliding contact with the inner wall of said pipe, a pivot ring for said feeler members, means for urging said feeler members radially outwardly whereby as each feeler member moves radially outwardly it pivots about said pivot ring to contact said well pipe and follow its surface variations in response to the urging of said urging means, back-up means in said tool for contact by said feeler members upon pivotal movement of said members about said pivot ring, and a reciprocating cone for contacting said feeler members at one portion of said feeler members, said urging means contacting said feeler members at another portion of said feeler members on the opposite side of said pivot from said cone.

18. In a well caliper tool for use in a well pipe having recording means, contact means for contacting the pipe, and transmitting means vfor transmitting surface variations in the well pipe from the contact means to the recording means, the improvement residing in the contact means, including a plurality of feelers each having a recess in its outer edge, a ring surrounding said feelers and contacting them in said recess to form a pivot for each of said feelers, back-up means in said tool for contact by said feelers upon pivotal movement of said feelers about said ring, and resilient means for urging said feelers radially outwardly whereby as each feeler moves under the urging of said resilient means it pivots in a radial plane about said ring.

19. In a pipe calipering tool having a housing adapted to be moved through a pipe. a plurality of feeler members pivotally mounted in said housing for pivotal movement in accordance with surface irregularities in the pipe, and a longitudinally movable transmitting means contacting the upper ends of said feeler members, the irnprovement residing in locking means for releasably locking said transmitting means against upward movement when the upper ends of saidl `f eeler members are being` urged outwardly to hold said feeler members in a retracted position within the housing.V l

20. In a pipe calipering tool having a housing adapted to be moved through a pipe, a plurality of feeler members pivotally mounted in said housing forpivotal movement in accordance with surface irregularities in the pipe, and a longitudinally movable transmitting means `Contacting the upper ends of said feeler members for transmitting the movements of said `feeler members in accord-v ance with the surface irregularities in the pipe, the improvement residing in locking means for releasably locking said transmitting means against upward movement and in a lowered position to hold said feeler members in a retracted position within the housing, said trans mitting means including a longitudinally extending rod with a transmitting member connected at its lower end References Cited in the file of this patent UNITED STATES PATENTS 2,322,343 Brandon June 22, 1943 2,544,609 McMahan Mar. `6, 1951 2,596,924 Fredd i May l`3, 1952 2,638,681 Kinley et al. May I9, 19153 2,771,685 Kinley Nov. 2 7, '1956 

